1. Field of the Invention
With regard to the classification of art, this invention is believed to be found in the general class entitled "X-ray Systems or Devices", and more particularly to the subclasses pertaining to "Electronic Circuits" for controlling functions of a portable X-Ray unit.
2. Description of the Prior Art
X-ray units are well known in the art. Several known U.S. patents disclosing cordless control systems for X-ray units are: U.S. Pat. No. 4,975,937, issued to Horton et al on Dec. 4, 1990, and U.S. Pat. No. 5,206,894 issued to Makrinos et al on Apr. 27, 1993.
U.S. Pat. No. 4,975,937 discloses a head activated flouroscopic control. This unit is primarily designed for use with a stationary base unit. It is specifically to be used in a surgical environment having one flouoscope per surgical suite. A head mounted transmitter is maintained in a powered up condition. This continual powered up arrangement may lead to premature battery drain. This type of control may expose the surgeon to unnecessary radiation.
U.S. Pat. No. 5,206,894 discloses an accessory for an X-ray system. This system uses a single button control which requires two successive actuations in order to perform an exposure. The second actuation must be performed within a specified time period before an exposure can take place. One disadvantage of this accessory is that the operator does not have instantaneous or momentary control of the Prep, and Expose functions of the X-ray unit. The selected time delay for the second actuation of the switch may not allow enough time for the operator to act or the complete rotation of the anode. This type of control may also lead to an excessive drain of the X-Ray units battery. If the time period is extended, the battery drain would be even worse. The U.S. Pat. No. 5,206,894 disclosure also suggest that the unit uses a single signal in two separate actuations to perform the prep and expose functions of the X-ray unit. It is believed that this control arrangement may accidentally actuate a nearby second X-ray unit, having a similar control system, by reflected signals.
It has been determined that there is a need for a cordless remote control which provides instantaneous or momentary control of the various functions of an X-Ray unit. This cordless control must meet regulatory agency requirements while being compatible with existing portable X-ray units. This cordless control should have multiple channels which are user selectable. These multiple channels when properly encoded will allow only one transmitter to operate a single receiving unit. This cordless control must also minimize draining of the batteries in the X-ray unit and the transmitter.